Electric cut-out



(No Model.) 2 Sheets-Sheet 1.

E. THOMSON. Y

` ELECTRIC CUT-OUT.

N0. 508,652. Patented NOV. 14,1893.

TNF, NATIQNAL LIYHOGRAPHING oMPANw,

wAsHrNmoN, u. c.

NrTED STATEs PATENT OFFICE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO THE THOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

ELECTRlC'CUT-OUT.

SPECIFICATION forming part of Letters Patent No. 508,652, dated November 14, 1893. Application tiled September 1'7, 1I9l. Serial No. 406,008- (No model.)

" scott, in the county of Essex and State of Massachusetts, have inventedy certain new and useful Improvements in Electric Cut-Outs, of

which the following is a specification.

My present invention relates to electric cut-offs for cutting off or breaking an electric circuit on occurrence of an abnormal current therein. Itis particularly to be applied to cutting off circuits in which the potentials are high enough to maintain arcs of considerable length, as to the case of cutting o transformer primary circuits, or interrupting the connection between the primary mains and the primary coils of transformers when for any reason a short-circuit of the primary, or short-circuit of the secondary of the transformer has occurred, or to the ca se where a short-circuit through lightning protective devices has been formed.

My invention provides a simple arrangement for cutting off arcs abnormally forming either to ground or between the sides of a cir-l cuit at high potential difference; my invention relating both to the particular device which is used as a cut-off and to the general combination with the circuit of a device having the functions which are to be described.

One of the features of my invention is that the interruption of the circuitis accomplished by drawing open the contact pieces and carrying one or both of them down into a body of oil which extinguishes the arc. One part of my invention, therefore, is broadly a switching device the contact parts of which are normally supported in air but which, on the formation of an arc, are immersed in a body of oil.

Another feature of my invention is the restoring action of the circuit breaker on the interruption of an arc and the nal locking of the arrangement in an open position when after several restorations the abnormal conditicns of short-circuit are shown to remain.

In the accompanying drawings Figure 1 is a vertical section of a cut-off embodying my invention. Fig. 2 'is a plan of the same. Figs. 3 and 4. are diagrams of systems with lmy invention applied thereto.

Figs. 5 and 6 show modifications.

Referring first to Fig. 3 A is a source of high potential currents, in this case alternating currents connected to mains Mleading to primary coil P of an induction coil or transformer, while S is the secondary coil of said transformer, and L, L, may be lights or other devices in the circuit thereof. At E, E and F are lightning arrester plates, the plate F being grounded at G, while the plates E, E slightly separated both from the ground plates and from each other form discharge electrodes in shunt across the terminals of the primary P. At K is placed my cut-off device, acting topinterrupt the connection between the mains M and the transformer on excessive current flowingas on a short circuit in the primary or secondary, or acting to interrupt the connection of the mains M to the discharge plates E, E on the occurrence of a short-circuit or arcing either between the plates E, E or between either of the plates and the ground plate F, such arcing being induced by lightning discharges between such plates. Interruption of the connection of the mains M in the manner stated `Jvould of course extinguish any arc at the discharge plates, or

lstop any short-circuit which might occur.

In Figs. 1 and 2, B, B, is a box containing preferably some non-conducting oil O, above which is a clear space. with a lid B which enables access to be had to its interior. At C is mounted an insulated contact Which may be made of a carbon block. Acontact lever D bears upon the contact block C, being held against the same The box is provided 9 IOO begins to descend.

by the action of a spring S. The lever D is pivoted, as shown, preferably beneath the surface ot' the oil. Lever D and contact C are connected in the circuit through connections m, n. In the connection to lever D is inserted a coil H, which when abnormally energized by current attracts or pulls .an armature or core I, attached to or arranged to actuate the lever D depressing it and carrying its contact surface resting on the block C down beneath the oil surface and thus interrupt any arc which may form between the contacts, or which may tend to continue after the lever D is drawn away from the block C. The armature or core I in the case of alter- `nating currents maybe made laminated as is well understood, and its motion may be retarded by a confined body of oil acting as a dash-pot in various ways. A separate dashpot might be provided but I have shown the core entering into its coil which forms an oil cylinder. It is desirable that the descent of the lever D and the core I shall be made quickly and hence I provide a valve V which allows `the oil to escape out of the piston core I and into the general oil space when the core When the descent has been accomplished and the arc is interrupted, the spring tends to raise the lever D ou account of the core having been released from the attraction of the coil. The release, however, on account of the closure of the valve V is made slowly and continues until the contact is again formed at C when if the abnormal conditions which provoked the descent of the lever D still exist, the actions above referred to would be repeated indefinitely were it not for other provisions which I have made. If therefore permanent harm has been done or permanent short-circuits have been caused the repeated opening which thus takes place calls attention to the condition of the apparatus, and at the same time is apt to be noticed at the generating` station. However, I provide in some cases an additional device thepurpose of which is to lock the lever D down and out of contact with the block .C A

upon the occurrence of a permanent short circuit demandingits repeated action. Many ways of accomplishing this result could be devised and'I onlyindicate one of them. At each descent of the piston corel, the oil under it imparts motion to the oil in the tube T, at the end of which is a small valve NV which lifts and allows at about thetime that the valve4 y V is lifted, a small gush of oil to work into portion carried by the lever D. When the.

pawl at R is thrown into engagement, lever D remains down and out of contact and all fm. Astructed that there is required for the conaction ceases while the line n remains opencircuited or out of connection with the line The locking device is preferably so continued lift of the piston in the cylinder .I a

` succession of pumping actions or movements of oil at not too great intervals apart, that is that the switch lever must be vibrating up and down within moderate intervals in order to continue to cause the piston in the cylinder .I to ascend to the position required for locking the pawl detent R. This is accomplished by allowing the piston in thelcylinder .I to have a slight leakage wherebyif the repetition of the actions of forcing oil is not made at sufficiently short intervals the piston drops back to its first position. In such case the actions which would call the device into operation at considerable intervals, such as would occur during thunderstorms by suecessive flashes would not canse the locking of the switch lever I) down, but a permanent short-circuit occurring on the line fn, would be followed at every contact of the lever D with a quick separation and immediate return to contact and again an instantaneous separation, this action being rapidly repeated. In such case the cylinder J would be unable to leak the Huid which was constantly accumulating and the ratchet pawl R would be thrown into engagement so as to hold the switch lever D open. The lever D `having been thus locked, it may be released by opening the box anddepressing the piston rod by button Q so as to release the catch.

Fig. 2 is a View looking down into the box B, B, and shows a duplication of parts whereby the apparatusis madeto act on both poles of a circuit or become a double pole arrangement. Bothof these maybe immersed in the same oil chamber or the sets could be put into separate oil chambers if desired, and both act together to interrupt short-circuits or disconnect the line, or they might act separately when thedevices are such as to demand separate action.

In many cases the locking devices above described would be unnecessary, as where it is only desired to rupture short-circuits hetween arrester plates due to momentary lightning discharges, the circuit being automatically restored to normal condition. As thus simplied, the apparatus is shown in Fig. 5.

In this case the valve V may be placed directly below the cylinder in which the core I moves, or as before, the lever D may be proy vided with a separate dash-pot having a valve similarly placed.

The means for extinguishing an arc, which consists in a non-conducting body of liquid beneath the arcing terminals, and into which one or both of said terminals are dipped when an arc is formed, may be applied to any forms of apparatus in whicharcs are liable to form. Fig. 6 shows the `principle applied to a simple hand switch, D being the switch lever, C its contact and O the body of oil.

What I claim as new, and desire to secure byrLetters Patent, is-

l. A device for rupturing arcs between terminals, consisting of a body ofnon-conductingliquid, terminals arranged normally above said liquid, and means for immersing at least one of them in said liquid when they are separated, substantially as described.

' 2. The combination with a closed box, of a body of non-conducting liquid partially illlng the saine, a terminal of an electric circult arranged above the surface of said liquid, and a second terminal in contact therew1th and arranged to move below the surface of the liquid when separated therefrom,

substantially as set forth.

The combination with a closed box, of a body of non-conducting liquid partially ill.- ing the same, a terminal of an electric circult arranged above the surface of theliquid, a lever forming a second terminal in contact with the first, and an electro-magnetic device operating to separate said terminals and immerse the lever in the liquid, substantially as described.

4. An electric switch having a fixed and a movable terminal, anda body of non-conducting liquid below such fixed terminal and in the path of such movable terminal.

5. A device for rupturin g arcs between electric terminals, consisting of a body of non conducting liquid below such terminals, and means for immersing one of such terminals in such liquid, consisting of an electro-responsive device connected to such terminals.

6. A device for rupturing arcs between terminals consisting of a body of non-conducting liquid below such terminals, and an electro-magnetic device connected mechanically and electrically to such terminals, and acting to immerse at least one of them in such liquid on the passage of a current therethrough.

7. A switch included in and protecting an electric circuit and having an electro magnetic device controlling and separating its contacts, an automatic locking device for holding such contacts apart, and means for throwing said detent automaticallyinto locking position only by the repeated separation of the contacts.

8. A switch included in and protecting an electric circuit, and having an electro-magnetic separating device for its contacts, a restoring device for the same, and a locking device for locking the contacts apart and connected to the electro-magnetic devices, so as to be operated only by the repeated action thereof.

9. A switch included in and protecting an electric circuit, and having an electro-magnetic separating device for its contacts, a restoring device for the same, and a retarded locking device for locking the contacts apart and tending to an unlocking position, and

connected to the electro-magnetic devices by a vslowly yielding connection, allowing return into unlocking position of the locking devices between widely separated impulses of the Velectro-magnetic devices, and bringing the locking devices into operation when such impulses are in rapid succession.

lO. The combination with two separable terminals, of a submerged solenoid, and a movable core connected with one of said ter- I ELIHU THOMSON.

W'itnesses:

JOHN W. GIBBONEY, BENJAMIN B. HULL.

kminals, whereby said solenoid and core form 

